ExOfficio BugsAway Purdom Hiker Sock 40% NatureSpun (Recycled Polyester)/ 40% Wool/ 19% Nylon/ 1% Spandex Imported The heel and toes of the ExOfficio Purdom Hiker Socks are reinforced with extra material to make them more durable. The reinforced arch support help keep you comfortable even after long days of hardcore hiking.